In the related art, for example, a system described in PTL 1 is known as an information display system as this type of vehicle information provision device. In the information display system described in PTL 1, an on-board device (device installed in a vehicle) such as an on-board navigation device and a portable terminal (external device) are connected in a wired manner or a wireless manner. If a connection state between the on-board device and the portable terminal is detected, a control device of the portable terminal supplies display data (external information for the vehicle) displayed on a screen of the portable terminal to the on-board device, and a control device of the on-board device displays the display data supplied from the portable terminal on the display of the on-board device.
This allows the user of the vehicle to view information that has been displayed on the screen of the external device such as the portable terminal, on the display (display unit) of the on-board device having a larger screen. When, for example, the on-board device such as a navigation system installed in the vehicle is applied as the display of the on-board device having a larger screen, it is possible to view the information displayed on the portable terminal, on the display of the on-board device having a larger screen provided in an optimal position inside the vehicle.